The specific aims of The Biostatistics and Data Management Core (BDMC) are: 1. To maintain data sets for all information derived from the Clinical Core, 2. To maintain data sets for all information derived from the Neuropathology Core, 3. To maintain data sets for all information derived from other ADRC components and from ADRC affiliated projects, 4. To maintain accuracy and confidentiality of all data entered into the centralized database, 5. To assist in the development of data collection forms, 6. To provide statistical consultation to projects, cores, and other investigators affiliated with the ADRC, 7. To routinely provide data tables to monitor patient and control subject enrollment and flow, 8. To provide periodic summaries of data to the Administrative Core, and portions of the centralized data to investigators when needed, and 9. To perform statistical analyses for ADRC cores and projects. The ADRC has purchased a SUN 4/490 computer and a site license for the data management and statistical package SAS, to replace the previous system which used M.U.M.P.S. on a DEC-10 computer. A computer program was written to archive data from the DEC-10 to the SUN 4/490. The BDMC will create a centralized data management system using SAS on the SUN 4/490 to receive, store, retrieve, and analyze data obtained from the various components of the ADRC. This system will provide a mechanism for ADRC investigators to access a variety of data relevant to their research endeavors, and to insure confidentiality and protection of intellectual property. Quality control procedures including standardized forms, double data entry, and regular audits will be put in place in order to insure accuracy of all data. Standardized forms have been developed for some data. The approval process by the Executive Committee for all manuscripts, grant submissions, and new projects using ADRC resources will include a review by the BDMC to insure the proper use and interpretation of statistical methods. Biostatistical consultation will be available from the BDMC for all projects using ADRC resources.